1. Field of the Invention
This invention pertains to aircraft instrumentation, and more particularly to devices for indicating when a sufficient speed has been obtained for safe take-off rotation of the aircraft.
2. Description of the Prior Art
Airspeed sensors and indicators have been used to indicate when an airplane has attained a predetermined airspeed deemed sufficient for safe rotation of the aircraft for take-off. However, if part of the airspeed is due to a headwind which decreases suddenly immediately after take-off, insufficient airspeed may remain for safe continuation of the take-off. As a consequence, rather than depend only upon airspeed as an indication that a safe speed has been reached for rotation, a safer procedure would be to use both an airspeed sensor and indicator and a ground speed sensor and indicator which indicates that a predetermined ground speed has also been reached or exceeded.